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return value for method asynchronous

I have a homepage where I call a class that reads a JSON with an asynchronous method, this method works good, but I need to return the value of the JSON to the main page.
MainPage.cs,
private void btnPrueba_Click(object sender, RoutedEventArgs e)
{
Dictionary<string,string> parametros = new Dictionary<string,string>();
parametros.Add("login", "12345678R");
parametros.Add("password", "123123");
objPrueba = new prueba();
objPrueba.doPost("http://prueba.es/login", parametros);
}
Class Post.cs,
public void doPost(string url, Dictionary<string, string> parametros)
{
System.Uri myUri = new System.Uri(url);
HttpWebRequest myRequest = (HttpWebRequest)HttpWebRequest.Create(myUri);
myRequest.Method = "POST";
myRequest.ContentType = "application/x-www-form-urlencoded";
//relleno variable con los parametros
foreach (KeyValuePair<string, string> D in parametros)
{
parametrosData = parametrosData + D.Key + "=";
parametrosData = parametrosData + D.Value + "&";
}
bool a = myRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), myRequest).IsCompleted;
string b = "1231232";
}
void GetRequestStreamCallback(IAsyncResult callbackResult)
{
HttpWebRequest myRequest = (HttpWebRequest)callbackResult.AsyncState;
// End the stream request operation
Stream postStream = myRequest.EndGetRequestStream(callbackResult);
// Create the post data
string postData = parametrosData;
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
// Add the post data to the web request
postStream.Write(byteArray, 0, byteArray.Length);
postStream.Close();
// Start the web request
myRequest.BeginGetResponse(new System.AsyncCallback(GetResponsetStreamCallback), myRequest);
}
void GetResponsetStreamCallback(IAsyncResult callbackResult)
{
HttpWebRequest request = (HttpWebRequest)callbackResult.AsyncState;
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(callbackRe sult);
using (StreamReader httpWebStreamReader = new StreamReader(response.GetResponseStream()))
{
string result = httpWebStreamReader.ReadToEnd();
//For debug: show results
Debug.WriteLine(result);
//RETURN VALUE result TO MAINPAGE.CS
}
}

You'd better use asynchronous functions, this would make your code much simpler.
You would have something like: (sorry for the bad formatting, I'm not familiar yet with StackOverflow editor...)
public async Task<string> doPost(string url, Dictionary<string, string> parametros)
{
System.Uri myUri = new System.Uri(url);
HttpWebRequest myRequest = (HttpWebRequest)HttpWebRequest.Create(myUri);
myRequest.Method = "POST";
myRequest.ContentType = "application/x-www-form-urlencoded";
//relleno variable con los parametros
foreach (KeyValuePair<string, string> D in parametros)
{
parametrosData = parametrosData + D.Key + "=";
parametrosData = parametrosData + D.Value + "&";
}
Stream postStream = await myRequest.GetRequestStreamAsync();
// Create the post data
string postData = parametrosData;
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
// Add the post data to the web request
postStream.Write(byteArray, 0, byteArray.Length);
postStream.Close();
// Start the web request
HttpWebResponse response = await myRequest.GetResponseAsync();
string result;
using (StreamReader httpWebStreamReader = new StreamReader(response.GetResponseStream()))
{
result = httpWebStreamReader.ReadToEnd();
//For debug: show results
Debug.WriteLine(result);
}
return result;
}
Then you can simply do:
private async void btnPrueba_Click(object sender, RoutedEventArgs e)
{
Dictionary<string,string> parametros = new Dictionary<string,string>();
parametros.Add("login", "12345678R");
parametros.Add("password", "123123");
objPrueba = new prueba();
string result = await objPrueba.doPost("http://prueba.es/login", parametros);
// You can use the string to update the GUI if you want, because this code is running on the GUI thread
}

WP7 Create helper class for easy use HttpWebRequest with POST method

Actually I have something like this:
private void createHttpRequest()
{
System.Uri myUri = new System.Uri("..url..");
HttpWebRequest myHttpRequest = (HttpWebRequest)HttpWebRequest.Create(myUri);
myHttpRequest.Method = "POST";
myHttpRequest.ContentType = "application/x-www-form-urlencoded";
myHttpRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), myHttpRequest);
}
void GetRequestStreamCallback(IAsyncResult callbackResult)
{
HttpWebRequest myRequest = (HttpWebRequest)callbackResult.AsyncState;
// End the stream request operation
Stream postStream = myRequest.EndGetRequestStream(callbackResult);
string hash = HashHelper.createStringHash("123", "TEST", "0216");
// Create the post data
byte[] byteArray = createByteArrayFromHash(hash);
// Add the post data to the web request
postStream.Write(byteArray, 0, byteArray.Length);
postStream.Close();
// Start the web request
myRequest.BeginGetResponse(new AsyncCallback(GetResponsetStreamCallback), myRequest);
}
void GetResponsetStreamCallback(IAsyncResult callbackResult)
{
HttpWebRequest request = (HttpWebRequest)callbackResult.AsyncState;
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(callbackResult);
using (StreamReader httpWebStreamReader = new StreamReader(response.GetResponseStream()))
{
string result = httpWebStreamReader.ReadToEnd();
ApiResponse apiResponse = (ApiResponse)JsonConvert.DeserializeObject<ApiResponse>(result);
}
}
It's good, it's working but now I must use these methods in every page and just change method createByteArrayFromHash which creates request. What if I want to create helper class that can help me to do this in something about 3 lines of code in page. How would you do that? I was thinking about this way but how to add request before response? Or would you do it another way? Thanks

Yeah, it's better to use async and await. Here is an example of such a wrapper:
public async Task<string> SendRequestGetResponse(string postData, CookieContainer cookiesContainer = null)
{
var postRequest = (HttpWebRequest)WebRequest.Create(Constants.WebServiceUrl);
postRequest.ContentType = "Your content-type";
postRequest.Method = "POST";
postRequest.CookieContainer = new CookieContainer();
postRequest.CookieContainer = App.Session.Cookies;
using (var requestStream = await postRequest.GetRequestStreamAsync())
{
byte[] postDataArray = Encoding.UTF8.GetBytes(postData);
await requestStream.WriteAsync(postDataArray, 0, postDataArray.Length);
}
var postResponse = await postRequest.GetResponseAsync() as HttpWebResponse;
if (postResponse != null)
{
var postResponseStream = postResponse.GetResponseStream();
var postStreamReader = new StreamReader(postResponseStream);
// Can use cookies if you need
if (cookiesContainer == null)
{
if (!string.IsNullOrEmpty(postResponse.Headers["YourCookieHere"]))
{
var cookiesCollection = postResponse.Cookies;
// App.Session is a global object to store cookies and etc.
App.Session.Cookies.Add(new Uri(Constants.WebServiceUrl), cookiesCollection);
}
}
string response = await postStreamReader.ReadToEndAsync();
return response;
}
return null;
}
You can modify it as you wish

Sending data to php from windows phone

I need to send some data from windows phone 7 to php page through POST method, I have the following code at wp7 side
public void SendPost()
{
var url = "http://localhost/HelpFello/profile.php";
// Create the web request object
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(url);
webRequest.Method = "POST";
webRequest.ContentType = "application/x-www-form-urlencoded";
// Start the request
webRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), webRequest);
MessageBox.Show("data sent");
}
void GetRequestStreamCallback(IAsyncResult asynchronousResult)
{
HttpWebRequest webRequest = (HttpWebRequest)asynchronousResult.AsyncState;
// End the stream request operation
Stream postStream = webRequest.EndGetRequestStream(asynchronousResult);
// Create the post data
// Demo POST data
string postData = "user_id=3&name=danish&email_id=mdsiddiquiufo&password=12345&phone_Number=0213&about_me=IRuel2&rating=5";
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
// Add the post data to the web request
postStream.Write(byteArray, 0, byteArray.Length);
postStream.Close();
// Start the web request
webRequest.BeginGetResponse(new AsyncCallback(GetResponseCallback), webRequest);
}
void GetResponseCallback(IAsyncResult asynchronousResult)
{
try
{
HttpWebRequest webRequest = (HttpWebRequest)asynchronousResult.AsyncState;
HttpWebResponse response;
// End the get response operation
response = (HttpWebResponse)webRequest.EndGetResponse(asynchronousResult);
Stream streamResponse = response.GetResponseStream();
StreamReader streamReader = new StreamReader(streamResponse);
var Response = streamReader.ReadToEnd();
streamResponse.Close();
streamReader.Close();
response.Close();
}
catch (WebException e)
{
MessageBox.Show(e.ToString());
}
}
and following on my localhost, to send the data to database
<?php
require_once("constants.php");
$user_id = $_POST['user_id'];
$name = $_POST['name'];
$email_id = $_POST['email_id'];
$password = $_POST['password'];
$phone_number = $_POST['phone_number'];
$about_me = $_POST['about_me'];
$rating = $_POST['rating'];
$query="INSERT INTO profile(User_ID,Name,Email_ID,password,Phone_Number,About_Me,Rating) VALUES ({$user_id},'{$name}','{$email_id}','{$password}',{$phone_number}, '{$about_me}' , {$rating})";
mysql_query($query,$connection);
mysql_close($connection);
?>
When I run the code I have no errors it means code is working fine, but no data is inserted in the database.

I think there is a better way than HttpWebRequest. That is WebClient. You can change the method there and append data like you do in get string. key=value&key2=value then when you invoke that request and get the response try debugging and getting the output from VS or if that is difficult simply assign he string to a textblock in the code. You will get to know if that page has been ever executed or not.
A sample code :
WebClient wc = new WebClient();
wc.UploadStringCompleted += new UploadStringCompletedEventHandler(wc_UploadStringCompleted);
wc.Headers["Content-Type"] = "application/x-www-form-urlencoded";
wc.Encoding = Encoding.UTF8;
Parameters prms = new Parameters();
prms.AddPair("email", email);
prms.AddPair("password", password);
wc.UploadStringAsync(new Uri(loginUrl), "POST", prms.FormPostData(), null);
private void wc_UploadStringCompleted(object sender, UploadStringCompletedEventArgs e)
{
// e.Result will contain the page's output
}
// This is my Parameters and Parameter Object classes
public class Parameters
{
public List<ParameterObject> prms;
public Parameters()
{
prms = new List<ParameterObject>();
}
public void AddPair(string id, string val)
{
prms.Add(new ParameterObject(id, val));
}
public String FormPostData()
{
StringBuilder buffer = new StringBuilder();
for (int i = 0; i < prms.Count; i++)
{
if (i == 0)
{
buffer.Append(System.Net.HttpUtility.UrlEncode(prms[i].id) + "=" + System.Net.HttpUtility.UrlEncode(prms[i].value));
}
else
{
buffer.Append("&" + System.Net.HttpUtility.UrlEncode(prms[i].id) + "=" + System.Net.HttpUtility.UrlEncode(prms[i].value));
}
}
return buffer.ToString();
}
}
public class ParameterObject
{
public string id;
public string value;
public ParameterObject(string id, string val)
{
this.id = id;
this.value = val;
}
}

First error: assuming that no error messages means success
Second error: gaping SQL injection holes
first fix: always assume queries will fail, and check for that condition:
$result = mysql_query($query) or die(mysql_error());
second fix: ditch the mysql_() functions and switch to PDO using prepared statements with placeholders. Boom. No more injection problems, and your code won't stop working on you when mysql_() is removed in a future PHP version.
ps..
3rd error: no quotes on your phone number value. So someone submits 867-5309, and you end up inserting -4442 because mysql saw it as two numbers being subtracted, not a string.

Push an variable into a method

I have an httpWebRequest to access an XML and save it locally then read it and show it to the screen. Problem is, i have to do this for more than one "pivot item", and the method that saves the xml is
private static void GetResponseCallback(IAsyncResult asynchronousResult)
and doesn't support adding a new variable to it so i can dynamically name the xml ("tmp"+xmlName+".xml") .
So the question is: How do i push a variable in the xml name ?
public class HttpWebReqMethod
{
public void httpRequestMethod (string url, string xmlName)
{
HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create(url);
httpRequest.ContentType = "text/xml";
httpRequest.Method = "POST";
httpRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), httpRequest);
}
private static void GetRequestStreamCallback(IAsyncResult asynchronousResult)
{
HttpWebRequest httpRequest = (HttpWebRequest)asynchronousResult.AsyncState;
// End the operation
Stream postStream = httpRequest.EndGetRequestStream(asynchronousResult);
string postData = "";
// Convert the string into a byte array.
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
// Write to the request stream.
postStream.Write(byteArray, 0, postData.Length);
postStream.Close();
// Start the asynchronous operation to get the response
httpRequest.BeginGetResponse(new AsyncCallback(GetResponseCallback), httpRequest);
}
private static void GetResponseCallback(IAsyncResult asynchronousResult)
{
HttpWebRequest httpRequest = (HttpWebRequest)asynchronousResult.AsyncState;
// End the operation
HttpWebResponse response = (HttpWebResponse)httpRequest.EndGetResponse(asynchronousResult);
Stream streamResponse = response.GetResponseStream();
StreamReader streamRead = new StreamReader(streamResponse);
string responseStream = streamRead.ReadToEnd();
using (var store = IsolatedStorageFile.GetUserStoreForApplication())
{
using (var istream = new IsolatedStorageFileStream(#"tmp" + xmlName + ".xml", FileMode.OpenOrCreate, store))
{
using (var sw = new StreamWriter(istream))
{
sw.Write(responseStream);
}
}
}
// Close the stream object
streamResponse.Close();
streamRead.Close();
// Release the HttpWebResponse
response.Close();
}

Here are two things you could do:
make GetResponseCallback not static, and store the xmlName in an instance variable
pass a state object (anything that has a property named xmlName, and something else to identify it by) to the request, and you can get it from the AsyncState
change GetResponseCallback's function to the following, and make the whole thing a callback "factory"
private static AsyncCallback GetResponseCallback(string xmlName)
{
return (IAsyncResult asynchronousResult) =>{
HttpWebRequest httpRequest = (HttpWebRequest)asynchronousResult.AsyncState;
// End the operation
HttpWebResponse response = (HttpWebResponse)httpRequest.EndGetResponse(asynchronousResult);
Stream streamResponse = response.GetResponseStream();
StreamReader streamRead = new StreamReader(streamResponse);
string responseStream = streamRead.ReadToEnd();
using (var store = IsolatedStorageFile.GetUserStoreForApplication())
{
using (var istream = new IsolatedStorageFileStream(#"tmp" + xmlName + ".xml", FileMode.OpenOrCreate, store))
{
using (var sw = new StreamWriter(istream))
{
sw.Write(responseStream);
}
}
}
// Close the stream object
streamResponse.Close();
streamRead.Close();
// Release the HttpWebResponse
response.Close();
}
}
EDIT to ADD:
the usage then changes to
httpRequest.BeginGetRequestStream(GetRequestStreamCallback(xmlName), httpRequest);

It's a callback method which is mapped to a specific delegate type, so no, you can't amend it's signature.
One option to resolve this would be to have a separate class such as this:
class HttpRequestState {
HttpWebRequest httpWebRequest;
string xmlFileName;
}
You can then set an instance of that class as the state object when you run the Begin callback:
httpRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), httpRequest);
would change to
httpRequest.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), new HttpRequestState() { httpWebRequest = httpRequest; xmlFileName = "tmp"+xmlName+".xml" });
Then of course, you can pull out the xmlFileName and the httpWebRequest like this:
HttpRequestState stateObj = (HttpRequestState)asynchronousResult.AsyncState;
HttpWebRequest httpRequest = stateObj.httpWebRequest;
string fileName = xmlFileName;

WP7 app never exits BeginGetResponse and goes into the callback function

I have the following code:
private void GetRequestStreamCallback(IAsyncResult asynchronousResult)
{
HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
// End the operation
Stream postStream = request.EndGetRequestStream(asynchronousResult);
//Console.WriteLine("Please enter the input data to be posted:");
//string postData = Console.ReadLine();
string postData = "my data";
// Convert the string into a byte array.
byte[] byteArray = Encoding.UTF8.GetBytes(postData);
// Write to the request stream.
postStream.Write(byteArray, 0, postData.Length);
postStream.Close();
// Start the asynchronous operation to get the response
IAsyncResult result =
(IAsyncResult)request.BeginGetResponse(new AsyncCallback(GetResponseCallback), request);
}
private void GetResponseCallback(IAsyncResult asynchronousResult)
{
HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
// End the operation
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
Stream streamResponse = response.GetResponseStream();
StreamReader streamRead = new StreamReader(streamResponse);
string responseString = streamRead.ReadToEnd();
Console.WriteLine(responseString);
// Close the stream object
streamResponse.Close();
streamRead.Close();
// Release the HttpWebResponse
response.Close();
allDone.Set();
Dispatcher.BeginInvoke((Action)(() => Debug.WriteLine("George")));
}
However when my code hits BeginGetResponse it never exits (and I do not hit a breakpoint in the GetResponseCallback function). I tried adding the BeginInvoke call, but I still never enter this method. This code works in a windows console app - it's on Windows Phone 7 that it doesn'teorg
Can anyone see what I am doing wrong?
Thanks.

If you have created the HttpWebRequest on the UI thread, then make sure you don't block the UI thread, otherwise you can deadlock.
The sample from the desktop .NET you have linked isn't optimized for the current phone networking stack. You should change the code so that you create the HttpWebRequest on a background thread.

I can't see what's wrong with your code (maybe a complete example of what you're trying to do may help) but here's a simple working example of a way of performing the action you want to do.
It posts some data to a URI and then passes the repsonse to a callback function:
Simply execute like this (use of a BackgroundWorker is not necessary but is recommended)
var bw = new BackgroundWorker();
bw.DoWork += (o, args) => PostDataToWebService("http://example.com/something", "key=value&key2=value2", MyCallback);
bw.RunWorkerAsync();
Here's the callback function it refers to:
(You can change this however is appropriate to your needs.)
public static void MyCallback(string aString, Exception e)
{
Deployment.Current.Dispatcher.BeginInvoke(() =>
{
if (e == null)
{
// aString is the response from the web server
MessageBox.Show(aString, "success", MessageBoxButton.OK);
}
else
{
MessageBox.Show(e.Message, "error", MessageBoxButton.OK);
}
});
}
Here's the actual method:
public void PostDataToWebService(string url, string data, Action<string, Exception> callback)
{
if (callback == null)
{
throw new Exception("callback may not be null");
}
try
{
var uri = new Uri(url, UriKind.Absolute);
var req = HttpWebRequest.CreateHttp(uri);
req.ContentType = "application/x-www-form-urlencoded";
req.Method = "POST";
AsyncCallback GetTheResponse = ar =>
{
try
{
var result = ar.GetResponseAsString();
callback(result, null);
}
catch (Exception ex)
{
callback(null, ex);
}
};
AsyncCallback SetTheBodyOfTheRequest = ar =>
{
var request = ar.SetRequestBody(data);
request.BeginGetResponse(GetTheResponse, request);
};
req.BeginGetRequestStream(SetTheBodyOfTheRequest, req);
}
catch (Exception ex)
{
callback(null, ex);
}
}
and here are the extension/helper methods it uses:
public static class IAsyncResultExtensions
{
public static string GetResponseAsString(this IAsyncResult asyncResult)
{
string responseString;
var request = (HttpWebRequest)asyncResult.AsyncState;
using (var resp = (HttpWebResponse)request.EndGetResponse(asyncResult))
{
using (var streamResponse = resp.GetResponseStream())
{
using (var streamRead = new StreamReader(streamResponse))
{
responseString = streamRead.ReadToEnd();
}
}
}
return responseString;
}
public static HttpWebRequest SetRequestBody(this IAsyncResult asyncResult, string body)
{
var request = (HttpWebRequest)asyncResult.AsyncState;
using (var postStream = request.EndGetRequestStream(asyncResult))
{
using (var memStream = new MemoryStream())
{
var content = body;
var bytes = System.Text.Encoding.UTF8.GetBytes(content);
memStream.Write(bytes, 0, bytes.Length);
memStream.Position = 0;
var tempBuffer = new byte[memStream.Length];
memStream.Read(tempBuffer, 0, tempBuffer.Length);
postStream.Write(tempBuffer, 0, tempBuffer.Length);
}
}
return request;
}
}